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Filter API Responses with Output Filters for the Java SDK

Temboo can help you reduce the complexity of API responses. Just specify one or more Output Filters when you call a Choreo.

What's an Output Filter?

It’s a filter that returns only the data that you care about!

Many APIs return a lot of complex JSON or XML data that can be difficult to parse. Let's take a look at how we can use Output Filters with the Java SDK to make API responses easier to work with.

Before You Begin

First, make sure that you've been through the Java getting started tutorial. The instructions below will show you how to build upon that tutorial by adding Output Filters.

FILTERING API RESPONSES

1In the getting started tutorial, we only printed out the Latitude and Longitude. We'll want to take a look at all of the outputs this time. Go ahead and replace the two println statements in your code with the following:

// print all of the outputs returned in the response
System.out.println(geocodeByAddressResults.getOutputs());

2Run the code and take a look at the console. See the XML response? It's massive and messy! What if the only information that we need for our application is the formatted_address as a string, and a list of the individual address_components that make up the address? Introducing Output Filters will allow us to extract only those data elements by adding just two lines of code. Let's try it:

3Add the following lines before the geocodeByAddressChoreo.execute() method.

How Did we do it?

Before showing some neat tricks to access the individual elements in the data, let's take a look at how the filter is created. As we saw above, each Output Filter is constructed with three parameters, in the format:

It may look confusing at first, but let’s step through recreating the two Output Filters from scratch to understand what's happening.

1A ChoreoInputSet object is used to specify the inputs that will be passed to the Choreo. Output Filters are also a type of Choreo input, so we'll add our inputs to the ChoreoInputSet object. To find the input set that we used to add the Geocoding Output Filters, just look back at the following line in your code:

// Get an InputSet Object for the Choreo
GeocodeByAddressInputSet geocodeByAddressInputs = geocodeByAddressChoreo.newInputSet();

After identifying the input that we'd like to filter, add .addOutputFilter as shown below.

2A result_label is anything we want it to be! It can be data123 or apple or Homer, as long as each output filter has a unique result_label of numbers or letters. This is how we tell Temboo to label a piece of result information when it is returned. In our example, we called our collection of address elements “components”. We called the full address "address".

3The data_path is used to identify, via XPath or a JSON path, the location of the particular item(s) that you want your output filter to return. For a more in depth explanation of data paths and data types, check out our guide on specifying JSON & XML paths for Output Filters. Here are the paths that we used when specifying our Output Filters earlier.

4The Choreo_output is the name of the Choreo output data that we're applying our output filter to. These names can be found in each Choreo's output section on our website. In most cases, the relevant Choreo output name will be Response, like in the screenshot below. However, as you can see we can also retrieve Latitude and Longitude in this particular Choreo.

5 When we combine all of this information, we have two Output Filters. One returns only the full formatted address as a string, and another returns a collection of elements that make up the address as a list.

// Get the full address as a string
geocodeByAddressInputs.addOutputFilter("address", "/GeocodeResponse/result/formatted_address", "Response" );
// Get the components of the address as a list
geocodeByAddressInputs.addOutputFilter("components", "/GeocodeResponse/result/address_component/long_name", "Response" );

Making use of the data

Previously, we printed all of the filtered outputs together. However, it can be even more useful to access each element individually.

We noted before that the "components" data is a list of individual elements that make up the address. To access those elements, we'll use the getResultsList() function, which returns a collection. Then we'll use a for loop to iterate through the list elements and print each out on new line. Let's give it a try:

2Since there is only one piece of data contained in the filter "address", we use the function getResultString() to print out the data element form this filter. Add the following line, beneath the for loop you created in the last step:

3If you run the code once more, you'll now see that for the "components" result, we've looped through each of the elements in our list and printed them out. We've also printed the full formatted address:

Here's the full code

The complete code takes advantage of two Output Filters. It should look like this:

You should now see individual outputs for each of the address "components" as a list, and the full "address" as a string printed to the serial monitor.

What's Next?

We've filtered some data! You can specify as many Output Filters as you need for each Choreo, so why not try adding your own third output filter to this example? If you'd like to try something different, you can try filtering the output from any of our 2000+ Choreos.

Once you've got your code up and running, you're ready to move on and do more. From monitoring your running applications, to moving your generated Temboo code to your preferred development environment and sharing it with colleagues, collaborators and friends - we've got you covered.